JP2005529459A - Method for manufacturing gas discharge device - Google Patents

Abstract

The present invention relates to a method for manufacturing a gas discharge device, particularly a discharge lamp or a plasma display unit. The discharge container containing the gaseous discharge medium is filled with the medium and the container is closed in a room cleaned by the filled gas in an overpressure state. This eliminates the need for a vacuum chamber, which has been necessary in the past, and allows undesired residual gas to be discharged along with cleaning. The overpressure can be neither too low nor too high, and is preferably kept in the range of 10 to 300, particularly 50 to 100 hPa.

Description

  The present invention relates to a method for manufacturing a gas discharge device, particularly a discharge lamp or a plasma display unit (PDP). A gas discharge device usually has a discharge vessel that houses a gaseous discharge medium. Therefore, the method for manufacturing a gas discharge device necessarily includes the steps of filling the discharge vessel with this sealed gas and sealing the discharge vessel.

  In the following description, the starting point is that a gas discharge device, for example, a discharge lamp, is at least mostly completed after blockade. The production method is therefore considered to be at least almost complete with the closure of the discharge vessel. This does not exclude that almost complete discharge lamps are still provided with electrodes, coated with a reflective film, or otherwise post-treated after the discharge vessel is sealed. However, the manufacturing method in the meaning of the claims is considered to have been completed with the closure of the discharge vessel.

[Conventional technology]
In general, a discharge vessel for a discharge lamp or PDP is provided with an exhaust tube or other connection that allows the discharge vessel to be evacuated and filled with an enclosed gas. These connections are generally sealed by fusion, and the protruding portion is then broken or cut off.

  The present invention relates to gas discharge devices designed specifically for dielectric barrier discharge, and more particularly to so-called planar radiators and PDPs. Both the flat radiator and the PDP have a flat discharge vessel, are configured to be quite large compared to their strength, and have two almost parallel flat plates. These plates need not be flat in the strict sense, but rather may be structured. Planar radiators are of particular interest for display and monitor backlighting in liquid crystal technology (LCD). Unlike an LCD, a PDP does not require a backlight. This is because self-emission occurs based on the generation of light by gas discharge. PDP has recently been used especially for TV devices.

  From the technical field of planar radiators or PDPs, it is also known how to evacuate and enclose the discharge vessel in a so-called vacuum furnace. A vacuum furnace is a space that can be evacuated and heated. Exhaust keeps undesired gases and adsorbates away to keep the filled discharge lamp gas as pure as possible, as in a normal exhaust tube.

  Exhaust tube solutions and similar measures lead to limitations on the geometry of the discharge vessel. The method in a vacuum furnace is costly due to the technical costs associated with the vacuum furnace and is also relatively time consuming.

[Description of the Invention]
An object of the present invention is to provide a method for manufacturing a gas discharge device, particularly a method for manufacturing a discharge lamp and a PDP, which is improved with respect to sealing and sealing of the discharge vessel.

  The present invention relates to a gas discharge device in which a discharge vessel of a gas discharge device is sealed after filling with gas, in particular, in a method for manufacturing a discharge lamp or PDP, the filling and blocking of the discharge vessel are cleaned with an overpressure filled gas. It relates to a method characterized in that it is carried out in the chamber (10).

  The present invention is based on the recognition that the sealing and sealing steps performed in a properly configured chamber are preferred over solutions with exhaust pipes or similar devices. The present invention offers the possibility of simultaneously treating a relatively large number of discharge vessel units. Furthermore, there are no boundary conditions for the discharge vessel structure to be optimized with respect to the exhaust and containment steps through the exhaust tube connection and the sealing of the exhaust tube connection. Instead, it is only necessary to be greatly freed up in the structure of the discharge vessel and to ensure the handling of the parts of the discharge vessel that are to be connected to each other for sealing and other steps necessary for sealing.

  On the other hand, the inventor starts from the premise that the vacuum furnace represents an unnecessary expense in terms of equipment costs and processing time.

  Instead, according to the invention, a chamber is used in which the filled gas for the discharge vessel is in an overpressure state. Thus, the chamber need not be evacuable. Instead, undesired residual gases are removed by cleaning the chamber. By eliminating the high vacuum sealing of the furnace and the evacuation step, the manufacturing process is significantly less costly and time saving.

  Furthermore, the thermal inertia of the chamber and in particular the chamber wall should be reduced and the chamber wall not thickened. This can be achieved by not excessively overpressure according to the present invention. Certainly, the present invention includes an embodiment in which the overpressure is up to, for example, 1 Pa. However, it is desirable not to exceed 300 hPa, more preferably 100 hPa.

  Thus, the chamber wall is at most 8 mm thick, preferably at most 6 mm, and optimally at most 4 mm in a large planar portion. In this case, of course, a contour structure may be generated.

  A preferred lower limit for the overpressure is 10 hPa, more preferably 50 hPa.

  The present invention further includes cleaning the chamber with an encapsulated gas as previously described. This cleaning is done by the simple construction of the chamber, otherwise the airtightness or intentionally provided opening allows the corresponding atmospheric gas to flow out due to overpressure and the atmosphere to maintain the overpressure. This is done by gas flowing into the chamber. Alternatively, the original gas outflow pipe may be used. However, even when using a gas outflow tube, the fact that overpressure can lead to possible airtightness or outflow from the leak is a major advantage of the present invention. In addition to the convenient atmospheric gas cleaning action at overpressure, it prevents the entry of contaminants into the chamber through the opening due to the discharge of pollutants in the room, for example, gas discharged from the discharge vessel part. Is done. As a result, an expensive seal that increases costs and, for example, takes care of opening and closing the chamber is eliminated.

  The chamber is preferably heatable, so this is in a general sense a furnace. Heating expels adsorbents and contaminants contained in certain components of the discharge vessel and initiates other processing steps as described in more detail below. In particular, heating is necessary for sealing the discharge vessel. The chamber is preferably heatable as a whole.

  As usual, there is also no technical problem or requirement for a heat resistant seal which results in considerable time and cost. For example, a flat contact between simple sealing surfaces is already sufficient for a satisfactory seal. This is because the remaining leak is not a problem due to internal overpressure in the chamber. However, the chamber may be a furnace in the original sense within the framework of the present invention, and thus may allow the indoor atmosphere to flow out through the original outlet as well as the leak. It has been confirmed that such an outlet may in particular be a gas outlet pipe.

  In order to shorten the processing time, it is desirable that not only the chamber can be quickly heated but also quickly cooled. For this reason, efforts are made to reduce the thermal inertia of the chamber. Furthermore, the chamber can be forcedly cooled. In particular, it is preferable to bring the cooling body into contact with the chamber in order to eliminate the flow of the cooling medium through the original chamber itself. The cooling body may be water-cooled, for example. Since the cooling body itself is not heated to the high processing temperature of the chamber, there is no problem with water cooling. Due to the flat contact to the chamber, the cooling body can cool the chamber quickly and easily.

  In order to drive out organic contaminants such as so-called glass wax, phosphor layers or binders in the reflective layer, the discharge vessel may be heated in an atmosphere containing oxygen, for example air, before filling. This atmosphere is preferably kept in a continuous stream to carry out the purged contaminants.

  Furthermore, the discharge vessel may be cleaned with an inert gas before sealing and possibly after heating in an atmosphere containing oxygen. Furthermore, in addition to the original discharge gas, that is, the gas that emits light at the time of discharge (it may be a mixed discharge gas) when the mixed gas is filled, another gas, particularly a rare gas, may be included. The discharge gas is preferably Xe. The rare gas to be added may be Ne and / or He, for example. In particular, in addition to the discharge gas, there may be other gases that exhibit a Penning effect with respect to the discharge gas, i.e. promote ionization of the discharge vessel through special excitation. This is true for Xe. In addition, when a buffer gas is added which helps to obtain the desired total pressure at the time of filling and in the finished cooled discharge lamp, in the partial pressure of the discharge gas and possibly the Penning gas which is given and tried to achieve. Good. In this case, the partial pressure and the total pressure at the time of filling must be adjusted so that the values sought to be achieved at the assumed operating temperature of the discharge lamp are achieved. The discharge gas Xe is preferably 60 to 350 hPa, preferably 70 to 210 hPa, particularly preferably 80 to 160 hPa at room temperature.

  Further, in a chamber used for filling a filled gas containing a rare gas, at least a rare gas freeze separation unit and / or a rare gas buffer device is provided as a gas outlet so that a part of the expensive rare gas can be reused. It is good to connect near the pipe. In order to prevent the noble gas freeze separation unit from becoming very large or to limit the consumption of the noble gas in the absence of such a freeze separation unit, the noble gas flow is stopped immediately after the discharge vessel is sealed. At this time, it is switched to a low-cost atmospheric gas or gas flow. This is especially air.

  In order to minimize mechanical stress as a whole, obtain a uniform temperature distribution as much as possible, and to perform accurate temperature control, the gas flowing into the chamber should have approximately the same temperature as in the discharge vessel at this point. is there. This means that the temperature deviation is not as large as +/− 100 K, in particular +/− 50 K, as much as possible, depending on the actual discharge vessel temperature.

  In this case in particular, the gas should be guided through a relatively long section on the gas inlet tube heated to the chamber temperature. The gas inlet tube may for example be perforated or cut in the thick part of the chamber and have a corresponding shape, for example a serpentine shape, for extension.

  In the present invention, a particularly simple embodiment is preferred in which the method steps necessary for heating, cleaning, filling and sealing the discharge vessel can be performed in the same room. This does not mean that the transport device must be included once. The conveying device is not continuously driven, but can be stacked and unloaded in batches.

  Therefore, in the case of such a chamber, it is necessary to separate the chamber parts from each other so that the interior of the chamber is emptied after processing, as in the vacuum furnace. In this case, the range of the chamber portions that are in contact with each other in the closed chamber is provided with a vacuum passage, and these contact surfaces can be sucked through the vacuum passage when the chamber is opened and closed. This suction helps to expel contaminants from the interior first (equivalent to a dust collector), and secondly it can push one chamber part against the other, and third. Thereby, an effective sealing action is obtained. That is, the vacuum passage discharges contaminants that enter from the outside before reaching the inside of the room. On the other hand, the vacuum passages enhance the backflow of gases present under overpressure inside the chamber and further prevent the entry of contaminants. The vacuum passage can likewise be connected to a rare gas recovery device or a rare gas freeze separation device for this purpose.

[Brief description of drawings]
Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. The individual features disclosed in this case may be the essence of the invention in other combinations.

[Advantages of the Invention]
FIG. 1 shows the installation according to the invention in a sectional view. The illustrated facility 1 is substantially planar and corresponds to the plane direction of a flat discharge lamp or PDP to be manufactured. A planar radiation discharge lamp or PDP to be manufactured is arranged in the interior space 10 of the metal block 2. A flat radiation discharge lamp or PDP to be manufactured is not shown, but is a known flat radiator designed for, for example, a dielectric barrier discharge, and a discharge vessel mainly comprises a cover plate and a base plate, Connected to each other at the edges. Electrodes are disposed inside or on the surface of the discharge vessel, and these electrodes are at least partially separated from the discharge space of the discharge lamp by a dielectric. Details of the structure are disclosed in subsequent prior applications by the same applicant, namely US Patent Publication Nos. 2002/163311 and 2002/163296. What is important in this connection is that the discharge vessel is filled with a filling gas as discharge medium during manufacture and then sealed.

  For this purpose, the discharge lamps are carried individually or in small numbers to the chamber 10 in the installation 1 of FIG. At that time, the flat metal cover 3 on the chamber 10 is removed. Since an SF6 glass piece is inserted between the base plate and the cover plate of each discharge lamp so as to give a sufficient distance between the two plates, the discharge space in each discharge vessel communicates with the chamber 10.

  Next, the metal cover 3 is placed and the chamber 10 is closed to the outside. The cover 3 is sucked and held firmly on the metal block 2 through the vacuum passage 6 shown in section, which opens towards the cover 3.

  The lower part of the metal block 2 below the chamber 10 is a relatively thin metal wall 11 having a thickness of 3.5 mm. In FIG. 1, it is drawn slightly thick in order to clarify the heating device described later. The metal cover 3 has a thickness of about 2 mm. For this reason, the chamber 10 is partitioned from the thin-walled equipment portion over most of the outer surface.

  As a whole, the metal block 2 can be heated by the electric heater 4 shown in cross section even in the area of the thin wall 11 below the chamber 10, and only a small thermal inertia occurs in the area of the thin wall. The cover 3 can also be heated by the heater 8 schematically shown.

  Furthermore, a gas can be introduced into the chamber 10 via the gas pipe 5 and the inlet E, and this gas flows through the chamber 10 and flows out from the pipe 9 and the outlet A. The chamber 10 can therefore be cleaned by the tubes 5 and 9. Both pipes meander in the metal block 2 as shown by the cross sections of the pipes 5 and 9, respectively, with a double cross section, so that the pipe length in the metal block becomes long and the gas is preheated into the chamber 10. Flows in and exits the chamber against some flow resistance in the tube 9. This flow resistance can be generated by an appropriately determined cross-sectional area of the tube 9 or an intentionally provided obstacle (throttle valve). Accordingly, dynamic pressure is generated in the chamber 10 during cleaning.

  The outlet A is connected to a rare gas freeze separation device so that the rare gas used as the sealed gas can be recovered.

  In summary, the chamber is heated, first cleaned with an oxygen-containing atmosphere, i.e. dry air, then flushed with an inert gas, i.e. argon, and finally composed of He, Ne and Xe under an overpressure of 250 hPa. Wash with mixed gas. Ne serves only as a Penning and buffer gas and He serves only as a buffer gas. At this time, since the temperature of the chamber 10 rises to about 500 ° C., the aforementioned SF6 portion is softened, and the cover plate supported thereby sinks and rests on the base plate. There is pre-prepared glass brazing (eg, manufacturer's Ferro Typ 100045), which softens at this temperature, resulting in an airtight bond between the two plates of the discharge vessel.

  Then stop the noble gas flow and switch to dry air for cooling.

  In order to accelerate cooling, a water-cooling type cooling block (not shown) is brought into contact with the metal block 2 in order to quench the metal block 2 by heat conduction. Due to the flat geometric structure of the metal block 2 and the thin wall properties of the walls 11 and the cover 3 in particular, the temperature in the chamber 10 drops relatively quickly. Therefore, the discharge lamp in the chamber 10 or a large number of discharge lamps therein can be quickly taken out. Therefore, production is carried out batchwise.

  While the cover 3 is placed on the chamber 10, the cover 3 is held by overpressure of the chamber 10 against the vacuum in the vacuum passage 6, but if insufficient, it is further mechanically clamped or pressed by a weight. It is good to fix by attaching. The overpressure in the chamber 10 results in a sustained slight outflow of ambient gas from the chamber 10 to the vacuum passage 6 through a contact surface that is not completely airtight between the cover 3 and the metal block 2. At the same time, since the vacuum passage 6 sucks contaminants entering from the outside, these contaminants do not reach the chamber 10. The combination from the course of cleaning in the chamber 10 on the one hand and the expulsion of contaminants on the other side ensures the rapid and thorough formation of the desired gas purity in the chamber 10. Accordingly, the vacuum passage 6 serves as a closing means, a sealing means, and an impureness preventing means.

  The loss due to gas outflow along the sealing surface between the cover 3 and the metal block 2 is insignificant because there is some gas consumption anyway due to the chamber volume and production per charge. Further, if economically meaningful, this range may be sucked and connected to the rare gas discharge unit.

  The chamber 10 can accommodate, for example, a 21 ″ lamp (42.7 cm × 32 cm). In this case, the chamber 10 has an internal dimension of approximately 50 cm × 40 cm × 5 cm. The vacuum passage 6 is for example 10 mm wide and 4 mm deep. There should be.

  In the above embodiments, the present invention has been described in detail based on a planar radiator, but the present invention is not limited to this. The advantageous effects of the invention can also be obtained in other types of discharge lamps, in particular in PDPs.

Schematic cross-sectional view of an apparatus for manufacturing a discharge device Schematic plan view of the device from FIG.

Explanation of symbols

  1 equipment, 2 metal block, 3 metal cover, 4 heater, 5 gas pipe, 6 vacuum passage, 8 heater, 9 gas pipe, 10 chambers, 11 metal wall, A outlet, E inlet

Claims (19)

In a gas discharge device in which a discharge vessel of a gas discharge device is filled with a sealed gas and sealed, particularly in a method for manufacturing a discharge lamp or PDP
A method characterized in that the discharge vessel is filled and sealed in a chamber (10) which is cleaned with an overfilled gas.   2. Method according to claim 1, characterized in that the chamber (10) is heatable.   3. The method according to claim 1, wherein the overpressure is at least 10 hPa.   4. A method according to claim 1, wherein a gas outlet pipe (9) is used for cleaning.   5. The method according to claim 1, wherein the chamber is cooled by contact with a cooling body that is water-cooled after the discharge vessel is sealed.   6. A method according to claim 1, wherein the discharge vessel is heated in an atmosphere containing oxygen before filling and optionally after heating.   7. A method according to claim 1, wherein the discharge vessel is cleaned with an inert gas before filling and optionally after heating in an atmosphere containing oxygen.   8. The method according to claim 1, wherein the discharge vessel is filled with a sealed gas containing a buffer gas for increasing the internal pressure in addition to the discharge gas filled for light generation. .   9. The discharge vessel according to claim 1, wherein the discharge vessel is filled with a sealed gas containing a rare gas having a Penning effect related to the discharge gas in addition to the discharge gas provided for light generation. Method.   10. The discharge gas to be filled for generating light is Xe, and the discharge vessel is filled with Xe having a partial pressure in the range of 60 to 350 hPa at room temperature. The method according to one of the above.   11. The method according to claim 1, wherein a noble gas freeze separator or a noble gas buffer is connected to the chamber (10).   12. The method according to claim 1, wherein the noble gas flow is stopped after the discharge vessel is sealed.   The method according to claim 12, wherein the gas is switched to a low-cost gas after the discharge vessel is sealed.   A sealed gas containing a discharge gas filled for light generation and a gas to be put into the chamber (10) after that at a temperature corresponding to the discharge vessel temperature existing at that time are introduced. 14. A method according to one of claims 1 to 13.   15. A method according to claim 1, wherein the chamber (10) has a wall thickness of at most 8 mm at most.   Method according to one of the preceding claims, characterized in that the discharge vessel is heated, cleaned, filled and sealed in the same chamber (10).   The chamber (10) can be opened by separating the two chamber parts (2, 3), and a pressing force is applied to the contact surface between the two chamber parts (2, 3) via the vacuum passage (6). The method according to claim 16.   18. The method according to claim 1, wherein the gas discharge device is a dielectric barrier discharge discharge lamp.   19. The method according to claim 1, wherein the gas discharge device is a planar radiator or PDP with a discharge vessel having two discharge vessel plates which are almost plane parallel.

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